Handling Soft Constraints in the Semantic Web Architecture

In this paper we present a proposal for representing soft CSPs within the Semantic Web architecture. The proposal is motivated by the need for a service-providing agent to reason about its commitments as soft constraints. The two essential requirements addressed are: the need to associate utility values with constraints, to reflect the relative importance of satisfying them, and the need to make statements about which constraints are satisfied and violated by a given solution. The proposal builds upon previous work in defining a Semantic Web Constraint Interchange Format (CIF), which itself builds on the proposed Semantic Web Rule Language (SWRL).The main contribution of this paper is a new ontology for representing soft CSPs; we also extend the previous form of CIF/SWRL. The soft CSP ontology is intended to be used with CIF/SWRL, but is also potentially usable with other constraint and rule representations.